北京某单位， 使用2台空调系统的冷却系，泵的流量200m3/h，扬程32m,轴功率21.26kW。

泵的装置是这样的，系出口有一个大的稳压罐，从稳压罐输送到所需要的冷却的空调系统中，然后又回到一个回水罐，从回水罐又回到泵的进口，这样一个闭式循环系统。调试中发现泵的出口压力低仅0.14MPa,泵达不到额定扬程32m的要求，用户认为泵不合格。

解决过程:现场观察到泵的出口压力确为0. 14MPa,即泵的扬程仅为14m,但电流却很大，达到了50A，而按泵的轴功率21.26kW计算应为40A左右。当泵关死阀门后泵出口压力能达到泵的关死点扬程。再进一步观察到，泵出口稳压罐的压力也是0. 14MPa，但回水罐的压力为0.12MPa,经过空调的冷却系统后，压力仅下降了0. 02MPa。根据上述情况判断认为空调冷却系统安装有问题，冷却水未进入空调冷却系统，即短路。出口的水直接回到了进口，也就是说未带上负荷。但安装公司不同意这个观点，认为是泵达不到性能所致。应先解决泵的问题。在设计院，用户，安装公司及泵厂共同商定下，决定关小泵出口阀门到泵的额定扬程值，然后用超声波流量计测量来的流量，结果流量为198m3/h, 基本达到系的额定流量200m3/h证实了上面分析是正确的，安装公司只得承认承没有问题，他们只好重新检查管路系统。渣浆泵厂家

A unit in Beijing uses two cooling systems of air conditioning system, with a flow of 200m3 / h, a lift of 32m and a shaft power of 21.26kw.

The pump is installed in such a way that there is a large pressure stabilizing tank at the outlet of the system, which is delivered to the required cooling air conditioning system from the pressure stabilizing tank, and then returned to a return water tank, and then returned to the inlet of the pump from the return water tank, such a closed circulation system. During the commissioning, it was found that the outlet pressure of the pump was only 0.14MPa, and the pump could not meet the requirement of 32m rated head. The user thought that the pump was unqualified.

Solution process: it is observed that the outlet pressure of the pump is indeed 0.14MPa, that is, the lift of the pump is only 14m, but the current is very large, reaching 50a, which should be about 40A according to the calculation of the shaft power of the pump of 21.26kw. When the pump closes the valve, the outlet pressure of the pump can reach the head of the pump's closing dead point. It is further observed that the pressure of the surge tank at the pump outlet is also 0.14MPa, but the pressure of the return water tank is 0.12mpa. After the cooling system of the air conditioner, the pressure only drops by 0.02MPa. According to the above conditions, it is judged that there is a problem in the installation of the air conditioning cooling system, and the cooling water does not enter the air conditioning cooling system, that is, short circuit. The water from the outlet goes directly back to the inlet, that is to say, without load. However, the installation company disagrees with this view, believing that it is due to the pump's failure to achieve performance. The problem of the pump should be solved first. Under the agreement of the Design Institute, users, installation company and pump factory, it was decided to turn off the rated head value from the outlet valve of the pump to the pump, and then measure the flow with ultrasonic flowmeter, the result flow was 198m3 / h, basically reaching the rated flow of 200m3 / h of the system, which confirmed that the above analysis was correct. The installation company had to admit that there was no problem, so they had to recheck the pipeline system.